THE EFFECTS OF THE CHESAPEAKE BAY IMPACT ON CALCAREOUS NANNOFOSSIL DIVERSITY

The purpose of this study is to assess the effects of the Chesapeake Bay Impact on calcareous nannofossil diversity during the Late Eocene. The Chesapeake Bay Impact occurred 35 million years ago (Ma), when a meteorite or asteroid struck the Chesapeake Bay and created a crater approximately 90 km in diameter. To examine the structure of the crater, continuous sediment core holes have been drilled and recovered in southeastern Virginia and the Delmarva Peninsula.

This study focuses on two U. S. Geological Survey continuous core holes: the Watkins Core from Newport News, VA, and the North Core from North, VA. Although the nannofossil assemblages from previous cores have been described, the nannofossil record from these two cores has yet to be examined. This research involves a detailed stratigraphic assessment of the calcareous nannofossil assemblages from the Late Eocene post-impact Chickahominy Formation in order to determine whether the impact produced a local extinction, and if so, whether this extinction was followed by a recovery interval. Preliminary results suggest that, despite its size, the Chesapeake Bay Impact did not significantly affect the local calcareous nannoplankton community.